Regulating the carbon shell structure of hollow cubic carbon for high performance electromagnetic wave absorption

Abstract

Herein, HCCs absorbers were synthesized by pyrolysis of phenolic resin, which was uniformly spread onto the surface of NaCl crystals. An investigation was undertaken to assess the effect of shell thickness on wave-absorbing capacity by altering the timing of the phenolic resin reaction. The morphology, composition and electromagnetic properties of the samples were also analyzed for different reaction times. Scanning electron microscopy (SEM) findings revealed a progressive increase in shell thickness of the HCCs from 28.728 nm to 92.654 nm, accompanied by a gradual enlargement in sample size. Compared to samples obtained at other reaction times, the sample reacted for 48 h exhibited favorable wave absorption properties attributed to its fitting shell thickness and impedance matching. Specifically, at a load rate of 5 wt% and the thickness of 2.7 mm, the maximum reflection loss reaches −50.5 dB with an effective absorption bandwidth of 6.2 GHz (11.8 GHz–18.0 GHz). Thus by altering the synthesis duration of phenolic resin is possible to effectively adjust the carbon shell morphology, thereby enhancing the capability for electromagnetic wave absorption.